Solve 100=3x^2+70

$$100 = 3 x ^ { 2 } + 70$$

Solve for x

$$x=\sqrt{10}\approx 3.16227766$$

$$x=-\sqrt{10}\approx -3.16227766$$

Steps by Finding Square Root

Swap sides so that all variable terms are on the left hand side.

$$3x^{2}+70=100$$

Subtract 70 from both sides.

$$3x^{2}=100-70$$

Subtract 70 from 100 to get 30.

$$3x^{2}=30$$

Divide both sides by 3.

$$x^{2}=\frac{30}{3}$$

Divide 30 by 3 to get 10.

$$x^{2}=10$$

Take the square root of both sides of the equation.

$$x=\sqrt{10} x=-\sqrt{10}$$

Steps Using the Quadratic Formula

Swap sides so that all variable terms are on the left hand side.

$$3x^{2}+70=100$$

Subtract 100 from both sides.

$$3x^{2}+70-100=0$$

Subtract 100 from 70 to get -30.

$$3x^{2}-30=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 3 for a, 0 for b, and -30 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\times 3\left(-30\right)}}{2\times 3}$$

Square 0.

$$x=\frac{0±\sqrt{-4\times 3\left(-30\right)}}{2\times 3}$$

Multiply -4 times 3.

$$x=\frac{0±\sqrt{-12\left(-30\right)}}{2\times 3}$$

Multiply -12 times -30.

$$x=\frac{0±\sqrt{360}}{2\times 3}$$

Take the square root of 360.

$$x=\frac{0±6\sqrt{10}}{2\times 3}$$

Multiply 2 times 3.

$$x=\frac{0±6\sqrt{10}}{6}$$

Now solve the equation x=\frac{0±6\sqrt{10}}{6} when ± is plus.

$$x=\sqrt{10}$$

Now solve the equation x=\frac{0±6\sqrt{10}}{6} when ± is minus.

$$x=-\sqrt{10}$$

The equation is now solved.

$$x=\sqrt{10} x=-\sqrt{10}$$